1. Field of the Invention
The present invention relates to an electrical storage device that includes a battery module with a plurality of battery cells housed in a battery house casing and a management circuit thereof.
2. Description of Related Art
Electric vehicles that use a rotating electric machine as a driving source and hybrid vehicles that use both an internal combustion engine and a rotating electric machine have recently been put to practical use. Those types of vehicles are mounted with a battery that supplies electrical energy to the rotating electric machine, and such battery to be mounted includes rechargeable secondary batteries such as a nickel-cadmium battery, a nickel-metal hydride battery, and a lithium ion battery.
A secondary battery is usually constituted as a battery module with a plurality of battery cells placed on top of one another, the bottom surface of a battery house casing is attached to the vehicle body through a module base, and a battery controller is mounted in the neighborhood thereof such as the top surface of the battery house casing or a side surface to manage the state of electrical storage, as disclosed in Japanese Laid Open Patent Publication No. 2004-319304.
A battery controller includes a built-in electric circuit, which needs to be grounded for its normal operation, and therefore the battery controller and the module base are often connected through a thick ground wire.